Clinical applications of BCI

Summary form only given. In recent years the clinical application of BCI has increasingly gained attention within the BCI community. Clinically, BCIs can be used to replace lost or to improve impaired function[1]. Consequently, BCIs have been applied to end-users with severe neurological disease leading to the so-called locked-in syndrome in which people have only residual muscular function for communication[2]. Here, end-users are provided with applications that allow for interaction in the broadest sense. With respect to improving impaired function stroke patients have been entering the focus of interest[3]. As end-users after stroke may experience multiple changes, BCI can be applied for affective, cognitive and motor rehabilitation. While a tremendous increase of BCI related research has lead to highly effective classification procedures, the translational gap of bringing BCIs to the people in need has only been recently addressed[4] and guidelines for this endeavor have been suggested[5,6]. Along with such guidelines, the framework of the user-centered design (UCD), which is well established in humancomputer interaction, has been transferred to BCI[7]. In an iterative process between end-users and developers a prototype is defined, developed, evaluated, and re-designed to optimally match the end-users´ needs. The major concept of the UCD is usability which takes into account the effectiveness, efficiency, and satisfaction with which a product is used[7]. End-users with disease identified easiness of use, functionality, and independent use as major criteria for daily use of BCI[8]. To account for these issues, BCIs for restoration and improvement of function were simplified with respect to calibration, set-up of the system, and number of electrodes[9-10]. Remote supervision is provided and evaluation data are continuously recorded. Two end-users in the locked-in state are using the P300-BCI controlled Brain Painting which allows for creative expression[11]. Bo- h have been using the BCI in their daily life for many hours and rated satisfaction and joy as being high and frustration low. As the BCI highly matches this particular endusers needs a cap with gel electrodes which imposes quite a strain on end-users, is tolerated[12]. No decline of performance has occurred in more than one year of BCI use despite the neurodegenerative disease. Accuracy is highly important for BCIs focusing on restoring lost function; for those which are aiming at improving impaired function, defining the appropriate brain activity for rehabilitation training is more important. While lost motor function is primarily addressed in rehabilitation, cognitive impairment is often neglected. However, cognition, and specifically attention and memory[13,14], are of utmost importance for the success of all rehabilitation and for activities of daily living. With BCI, specific EEG components linked to cognition can be fed back to the subject[15]. Stroke patients were provided with feedback of sensorimotor rhythms and of slow cortical potentials to improve memory and attention. Efficiency of information processing and memory performance increased[16]. The neurofeedback guided cognitive training can be conducted at the end-users´ home with remote supervision of the trainer again taking into account the aspects of usability. To conclude, the UCD provides a framework for bridging the translational gap in BCI research by focusing on the needs and the requirements of the end-users[7]. BCI controlled applications have been developed that meet these requirements and can, thus, be transferred from the researchers´ laboratories to the endusers´ home and, most importantly, are used by the targeted endusers without experts being physically present. Easy to use soft-and hardware, and remote support upon request are mandatory. Adopting the UCD for BCI research and development will allow the community to define indication criteria to optimally design a BCI for the indivi